The present invention relates to a vacuum processing apparatus for processing a sample to be processed disposed on a sample stage in a depressurized processing chamber inside a vacuum vessel using plasma formed in the processing chamber.
In a vacuum processing apparatus that processes a workpiece such as a semiconductor wafer, for example, a workpiece such as a semiconductor wafer held on a sample stage including an electrostatic chuck is processed by introducing processing gas into a vacuum processing chamber in a depressurized state, putting the introduced processing gas in a plasma state, and causing a chemical reaction with a radical or electron sputtering.
In the vacuum processing apparatus, processing gas is used, and a reaction product adheres to an inside of the vacuum processing chamber when the processing gas is put in a plasma state to process a workpiece (wafer). When the reaction product adheres to a surface of a component disposed inside the processing chamber, there arises a problem that the reaction product becomes a fine particle, peels off from the surface due to deterioration of the component, and falls to adhere to the wafer, etc. as a foreign material, thereby contaminating the wafer. To suppress this problem, a reaction product, etc. that causes a foreign material is removed by periodically replacing or cleaning the component in the processing chamber, or a process of reproducing a surface of each component is performed (maintenance). During the maintenance, the inside of the processing chamber is open to an atmosphere of an atmospheric pressure, processing may not be performed, and operation of the apparatus is suspended. Thus, efficiency of processing decreases.
Further, recently, the semiconductor wafer corresponding to the workpiece has increased in diameter. For this reason, the vacuum processing apparatus increases in size, individual components included therein increase in size, and weights thereof tend to increase. In addition, it is not easy to remove, move, or mount the components, maintenance is expected to take a long time, and there is concern about a further decrease in maintenance efficiency.
For example, a technology for improving maintenance efficiency of such a vacuum processing apparatus is disclosed in JP-2005-252201-A. In addition, for example, an electrostatic chuck used in a vacuum processing chamber is disclosed in JP-2005-516379-A.
JP-2005-252201-A discloses a vacuum processing apparatus that includes an upper inner cylinder chamber and a sample stage included in a processing chamber for processing a workpiece inside an outer chamber, and a lower inner cylinder chamber disposed on an exhaust portion side. In the present vacuum processing apparatus, during maintenance, a discharge chamber base plate, which is disposed above the upper inner cylinder chamber and included in a discharge chamber for generating plasma, is lifted upward such that the discharge chamber base plate is rotated using a hinge portion disposed on a conveyance chamber side as a fulcrum, and the upper inner chamber is lifted upward and removed from the outer chamber by ensuring a work space for the upper inner chamber. Further, a technology is described. In this technology, a sample stage base plate, to which a ring-shape support base member (sample stage block) including a support beam disposed and fixed around an axis using a center of a sample stage in a vertical direction as an axis is fixed, is lifted upward such that the sample stage base plate is rotated using a hinge portion disposed on a conveyance chamber side as a fulcrum, and a lower inner chamber is lifted upward and removed from an outer chamber by ensuring a work space for the lower inner chamber. When support beams are axis-symmetrically disposed using a center of the sample stage in the vertical direction as an axis (that is, a gas flow path shape with respect to a center axis of the sample stage is substantially in axial symmetry with respect to the same axis), gas (processing gas, a particle in plasma, or a reaction product) in a space on the sample stage inside the upper inner cylinder chamber is discharged through the lower inner cylinder chamber by passing through a space between the support beams. In this way, a flow of gas in a circumferential direction of the workpiece becomes uniform, and uniform processing of the workpiece may be performed.
When the technology of lifting up the discharge chamber base plate and the sample stage base plate using the hinge portion as the fulcrum is applied to maintenance of a workpiece increased in diameter, the discharge base plate or the support beam to which the sample stage is fixed increase in size, and weights thereof increase. Thus, there is concern about having difficulty in lifting the discharge base plate or the support beam upward by hand, and difficulty in ensuring a workspace for the upper inner cylinder chamber or the lower inner cylinder chamber. In addition, maintenance of the exhaust portion is performed by peering from an upper portion of the outer chamber. However, there is concern about having difficulty in sufficient cleaning, etc. since a hand does not reach the portion due to an increase in size of the apparatus. Furthermore, there is concern about an unstable foothold in irregular maintenance such as maintenance or replacement of a component included in the discharge base plate or the sample stage which is lifted upward. Even when the discharge base plate or the support beam to which the sample stage is fixed is lifted up by a crane, etc., the two latter ones are not resolved.
In addition, JP-2005-516379-A discloses a cantilevered substrate support which may be attached to and detached from a vacuum processing chamber by passing through an opening provided in a side wall of the vacuum processing chamber (in a horizontal direction) and is mounted with an electrostatic chuck assembly. In a case in which this technology is applied to maintenance of a workpiece increased in diameter, since the substrate support is vacuum-sealed at an opening of a chamber-side wall, there is concern that load on a vacuum seal portion may increase when a weight increases, and it is difficult to maintain vacuum. In addition, a gas flow path shape with respect to a center axis of a sample support is not in axial symmetry with respect to the same axis due to a cantilever, so that a flow of gas in a circumferential direction of the workpiece becomes nonuniform, and it is considered that uniform processing on the workpiece becomes difficult.
As a technology for solving such a conventional technology, there has been a known technology for improving efficiency of maintenance by dividing the whole portion into a portion included in a sample stage or an electrostatic chuck and a plurality of portions disposed on upper and lower portions of the sample stage or the electrostatic chuck and then sealing the portions to form a vacuum vessel, rotating and moving the portion included in the sample stage or the electrostatic chuck in a horizontal direction of a main body of a processing unit in a state in which the portion is connected to a vacuum processing apparatus or the main body of the processing unit, and allowing the upper and lower portions to be successively removed. A technology disclosed in JP-2015-141908-A has been conventionally known as an example of such a technology.
JP-2015-141908-A discloses a vacuum processing apparatus having a vacuum vessel that includes a cylindrical lower container disposed on a base plate, a ring-shaped sample stage base that includes a support beam supporting a sample stage therein, a cylindrical upper container, a cylindrical discharge block, and a lid member made of a dielectric which closes an upper portion of the discharge block. In a processing unit of the present conventional technology, due to a microwave supplied into a processing chamber, which is formed inside the vacuum vessel by sealing members of the vacuum vessel, by permeating the lid member or a high frequency electric field in a very high frequency (VHF) or ultra high frequency (UHF) band and a magnetic field from a solenoid coil disposed to surround a periphery of an upper part and a side part of the discharge block, an atom or a molecule of processing gas supplied into the processing chamber is excited to form plasma, and a substrate-shaped sample such as a semiconductor wafer placed and held above an upper surface of the sample stage is processed.
Further, at the time of performing maintenance such as cleaning or replacement and inspection on a member included in the vacuum vessel or a member included in a surface inside the processing chamber, after setting a pressure of an inside of the processing chamber to atmospheric pressure or a pressure value approximate to a degree that may be regarded as the atmospheric pressure, the lid member or the discharge block is separated from others, the upper container is removed, or the sample stage base is horizontally rotated for each sample stage and moved and evacuated from the lower container on a lower side or the base plate and an upper side of a vacuum pump such as a turbo molecular pump disposed below the base plate. An operator who performs replacement, maintenance, and inspection of the upper container or the lower container, or replacement, maintenance and inspection operations of the sample stage or a component connected thereto may ensure a sufficient space to perform the operations in a state in which each component is removed from another component or another component is evacuated, improve efficiency of work, and shorten a time during which the vacuum processing apparatus does not process the sample to improve efficiency operation thereof.